Apparatus for Shell Freezing a Liquid Content in a Container

Abstract

An apparatus for shell freezing a liquid content in a container, comprising an endless loop conveyor having a conveying length adapted to convey plural containers such as pharmaceutical vials, incorporating plural rollers to spin the containers as they are conveyed by the conveyor, and a return length, along at least part of the return length the rollers are immersed in a cooling liquid at a temperature below the freezing point of the liquid content of the containers, and along the conveying length the rollers are entirely above the surface of the cooling liquid. A preferred cooling liquid is liquid nitrogen, the evaporating vapour of which can be used to shield vials on the conveying length.

1 . An apparatus for shell freezing a liquid content in a container, the apparatus comprising an endless loop conveyor having a conveying length adapted to convey plural containers in a conveying direction and incorporating plural rollers to spin the containers as they are conveyed by the conveyor, and a return length, characterised in that the return length of the conveyor is configured such that along at least part of the return length at least part of the rollers is immersed in a cooling liquid at a temperature below the freezing point of the liquid content of the containers, and the conveying length is configured such that along the conveying length the rollers are entirely above the surface of the cooling liquid. 
   
   
       2 . Apparatus according to  claim 1  characterised in that:
 the conveyor is adapted to convey plural cylindrical vials containing a liquid content which is an aqueous solution or suspension of a drug compound or vaccine, in a horizontal conveying direction which is perpendicular to their longitudinal cylindrical axis,   the conveyor incorporates plural rollers comprising part of the conveyor, which are rotated about a rotation axis aligned horizontally across the conveying direction as the conveyor conveys the vials, the rollers adapted such that a conveyed vial rests on a pair of rollers which are adjacent in the conveying direction such that the rotation of the rollers imparts rotation to the vial resting thereon,   the rollers are cooled by their immersion in the cooling liquid such that along the conveying length they are at a temperature below the freezing point of the liquid content.   
   
   
       3 . Apparatus according to  claim 1  characterised in that the conveyor is configured as an endless loop conveyor, having a conveying length which is above the return length. 
   
   
       4 . Apparatus according to  claim 1  characterised in that the cooling liquid is a liquefied gas. 
   
   
       5 . Apparatus according to  claim 4  characterised in that the cooling liquid is liquid nitrogen. 
   
   
       6 . Apparatus according to  claim 4  characterised in that the conveyor is configured that at least part of the rollers along the conveying length are also exposed to cold gaseous nitrogen from evaporating cooling liquid. 
   
   
       7 . Apparatus according to  claim 4  characterised in that a trough is provided below the conveying length, the trough configured such that the return length, or part at least of the rollers, dips into the cooling liquid, and the trough is provided with upwardly extending sidewalls of a height sufficient that cold vapour evaporating from the cooling liquid forms a cloud around the upper conveying length. 
   
   
       8 . Apparatus according to  claim 7  characterised in that the trough is double walled with a void between the walls, and cold vapour evaporating from the cooling liquid in the trough is able to flow into this void between the walls. 
   
   
       9 . Apparatus according to  claim 1  characterised by a conveyor constructed so that along the return length rollers are immersed into the cooling liquid with their rotation axis vertical. 
   
   
       10 . Apparatus according to  claim 4  characterised by a downstream end off-loading means to remove the containers, containing their frozen content, and to deliver the containers to a receiving tray wherein the receiving tray is kept cool at a temperature below the freezing point of the liquid content so that the liquid content remains frozen whilst the containers are waiting on the receiving tray by means to expose the underside of the tray to cold vapour of the evaporating cooling liquid.